An organic light-emitting device includes an anode, a cathode, and a thin film that contains a fluorescent organic compound and is interposed between the anode and the cathode. When electrons and holes are injected from the respective electrodes, excitons of the fluorescent compound are generated and the light emitted by the excitons returning to their ground state is utilized by the device.
Recent advancement of organic light-emitting devices has been remarkable and suggested possibilities of applying the devices to a wider range of usages. This is because they can achieve high luminance with low voltage, a wider range of emission wavelengths, rapid response, and reduction in thickness and weight.
However, under existing conditions, further improvements are needed in terms of luminance of the optical output and conversion efficiency. Moreover, many problems on durability remain such as changes over time resulting from long-time uses and deterioration caused by oxygen-containing atmosphere gas and humidity.
In order for devices to be applicable to full-color displays and the like, emission efficiency and the color purity must be high. However, this is not yet achieved. Organic light-emitting devices that achieve high color purity, high emission efficiency, and high durability and materials that can realize such organic light-emitting devices are desired.
Although Patent Citations 1 to 4 disclose materials for emission layers that achieve higher emission efficiency, none of these materials is sufficient for practical application. Development of new materials that achieve high quantum yield is desired.
Patent Citation 1
    Japanese Patent Laid-Open No. 1-289907Patent Citation 2    Japanese Patent Laid-Open No. 2-247278Patent Citation 3    Japanese Patent Laid-Open No. 8-113576Patent Citation 4    Japanese Patent Laid-Open No. 11-12205